The commute was doing more than you think
A walk to a bus stop, stairs at the office and a wander to a meeting room happened without a decision. Remove the building and you remove the movement that came free with it.
Replacing that with one scheduled workout rarely sticks because it needs a decision, clothes and a block of time. Small amounts need none of those.
Anchor movement to something that already happens
The reliable trigger is an event: the kettle going on, a call on hold, the ad break, or the gap between meetings.
Pick two anchors to start with. That is small enough to do and enough to prove the idea before extending it.
Two minutes is a real unit, not a consolation prize
Short bouts count towards general activity and accumulate across a day. Frequency is easier to control on a busy day than duration.
Treat two minutes as the default and ten as a bonus. Aiming low is how the habit survives a bad week.
Make the desk setup work against sitting still
Keep the water glass small, take calls standing and put regularly used things slightly out of reach. It all adds movement.
If you use a sit-stand desk, alternate. The goal is changing position often, not holding one posture.
Track accumulation, not adherence
A plan followed 60% of the time reads as failure. The same activity logged as a running total reads as progress.
Look for tools that show what you have done rather than what you missed.